Plug for oil and gas wells



s N A P s u. F.

PLUG 'FOR ILAND `GrAs wELLs Filed July' 27,; 1940 2 sheets-sheet 2lllvll Patented Mar. 9, 1943 UNETED STATES PATENT.

erich 9 Claims.

.This invention relates to plugs for use in oil and gas wells and oneobject of this invention is to produce a plug which, after being loweredby means of cable tools to the desired position in the bore hole of awell, may be set or securely anchored at such position by an upwardstress exerted thereon by such tools.

Another object is to produce such a plug which embodies a frangibleconnector element by means of which the plug proper, 4after beinganchored in the well bore hole, may be disconnected from the cable toolsused in placing the same in position.

A further object is to produce such a plug which, in its make-up,includes improved anchoring means operated by fluid pressuretherebeneath for preventing the plug from rising within the bore hole.

A still further object is to produce such a plug which in its make-up,includes means for utilizing the fluid pressure therebeneath fortightening it in the well bore hole and increasing its resistance tomovement therein.

These -as well as other objects which will be apparent to those' skilledin this particular art, I attain by means of the plug described in thespecification and illustrated in the drawings ac-- companying andforming part of this applic-ation.

In a general way, the plug of this invention comprises a resilient`deformable packing element, a packing element expander, a lock for thepacking element expander, a set of anchoring slips, a slip carrier, aslip actuator provided with Wiper springs for yieldingly resistingmovement of the actuator to different positions within the well borehole, a sub for Connecting the plug to the lowermost member of a stringof cable setting tools, and a frangible connector element by means ofwhich the sub is connected to the packingl element expander.

In the drawings, throughout which similar elements are denoted by likecharacters, and which illustrate a preferred embodiment of this inven-ltion:

Figure l is a view partially in elevation and partially in section of aplug embodying this invention. This view illustrates the plug incontracted position ready to be run or lowered to position within thebore hole of a well.

Fig. 2 is a view similar to that of Fig. 1 but illustrates the plugafter it has been lowered to position in the well bore hole and thenexpanded; the frangible connector element above referred to, still beingintact. l

Fig. 3 is a View similar to that of Fig. 2 after the plug is anchored inthe well bore hole and the frangible' connector element has been broken.

Figs. 4, 5 and 6 are enlarged views of the slip carrier; Fig. 4 being aperspective view, Fig. 5 a top plan and Fig. 6 a sectional View taken onthe line VI-VI of Fig. 5.

Fig. '7 is a perspective View of the slip expander with its wipersprings.

, Fig. 8 is a top plan View of the segmental snubbing ring which locksthe plug in expanded position;

Fig?. 9 is a sectional view of said ring taken `on line IX-IX of Fig. 8;and

Fig. 10 is a perspective View of one of the slips.

The resilient deformable packing element I0 made from natural orsynthetic rubber, when not deformed, as shown in Fig. l, has the form ofa hollow cylinder with parallel inner and outer wall surfaces throughoutthe major part of its length. The lower edge portion of the packingelement is secured to a tubular metal member Il while its upper endportion is secured to a metal ring or band-like member i2. The packingelement is preferably secured to tubular members H and l2 in the mannerdisclosed in Patents Nos. 2,106,859 and 2,136,597 issued to me on Feb.l, 1938, and Nov. 15, 1938, respectively.

Band-like member l2, by means ofsuitable screws I3, is secured to slipcarrier I4 below flange l5 of said carrier.

Packing element it), tubular member il and slip carrier Ill when securedtogether constitute a unit which is mounted on the packing elementexpander, which not only functions as an expanderfor the packingelement, but as a support forsaid unit.

The expander comprises a cylindrical bottom portion It which, having asnug sliding fit with thev inner cylindrical surface of tubular memberIl, serves asy a piston` or plunger head; a conical porti-on' ll whichmakes a snug lit with the tapered lower portion i8 of packing elementl0; a stem-like parthaving a smooth cylindrical portion I9 which makesa" tight t with the inner cylindrical wall -ofpackingelement IB; aportion 20 which is' provided throughout its length with buttressthreads', asdisclosed in Figs. l, 2 and 3, and an upper cylindrical endportion 2l of somewhat reducedy diameter'.

The lower end of tubular member H is closed by a closure disk 22,- whichis Welded to the lower end of said'V member by a metal weld 23. Arelatively small hole'- 24 is drilled through tubular member l ladjacent its bottom for a purpose to be later referred to.

Slip carrier I4 is provided with a central bore 25 having a diametersuch that it clears the threads of the threaded portion of the expanderstem. The upper end of this bore is chamfered as shown at 26 and thebore at its lower end connects with a circular pocket-like cavity 21having its wall inclined inwardly from its top to its bottom. Thiscavity serves as a housing for the segmented snubbing ring, made up ofidentical parts 23, 28a. and 28h, and because of its inclined wall,tends to releasably hold said ring in contact with the threaded portionof the stem of the expander. As shown in Figs. 8 and 9, the outerperipheral surface of the ring isY inclined to conform to the incline ofthe wall of pocket 21, while its inner peripheral surface vis providedwith threads for cooperating with the buttress threads of the threadedportion of the stem.

While the slip carrier i4 is cal, it is provided with -a series(preferably four) of longitudinally extending cut away portions as shownin Figs. 4 and 5 to provide flat slip bearing surfaces 29 which inclineinwardly toward the top of the carrier. l

Each inclined surface 29 is provided with an undercut slot 33 forreceiving the tongue 3l of one of the slips 32. Beside the tongue, whichdovetails with one of the slots 30, each slip has a curved outer toothedface 33 and side portions 34-34 which bear against inclined bearingsurfaces 29.

The slip actuator which as an entirety is numbered 35 is of tubularform, as shown in Fig. 7 and is provided with a series of fourrectangular windows or openings 36 one for each slip, and through whichthe slips project as shown in Figs. 1, 2 and 3. Openings 36 are soplaced that the actuator has a broad band 31 at its top and a narrowerband 38 at its bottom.

A series of four wiper springs 39, secured at their lower ends to band38 have their upper or free ends bearing against the outer surface ofband 31. These wipersprings overlie portions 49 which separate openings33 and connect bands 31 and 3S.

The inner diameter of lower band 38 1s such as to permit it to slidereadily on the cylindrical surface portions of slip carrier I4.

The frangible connector element before referred to and which is numbered4I, is of tubular form, and has the same outside diameter as portion I9of the expander stem. This connector element snugly nts the reducedupper end portion 2l of the expander stem and is secured to the expanderstem by a weld joint 42. The upper end of the connector element isthreaded into athreaded bore in the lower cylindrical end 43 of sub 44as shown at 45, and approximately midway between the top of the expanderstem and the bottom of the sub the connector element is provided with aseries of drilled through holes 46 which weaken the element andpredetermine the force required to fracture the same, after the plug issecured in position within the well bore hole.

Sub 44 is provided with a threaded end 46 .for the purpose of connectingthe same to the mating end of a set of cable tool jars (not illustrated)forming part of a string of cable setting tools which are run on a wireor manila cable extending through the well bore to the surface. Sub 44is also provided with wrench squares 41 and a shoulder 48 which extendsoutwardly and overlies the outer cylindrical surface 49 of cylindricalportion 43 at the lower end of the sub. Lower face B of this cylindricalportion is beveled as generally cylindrishown in Figs. 1, 2 and 3 tocorrespond with the upper beveled surfaces 5I of slips 32 (see Fig. 1).

Before sub 44 is screwed home on the upper end of frangible connectorelement 4I the lower ends of tongues 3l of the slips 32 are enteredwithin the upper ends of slots 3E] of the slip carrier I4. With theslips in this position, the distance between curved faces 33 ofoppositely positioned slips is less than the inner diameter of bandportions 31 and 38 of the slip actuator, thus permitting the slipactuator to be slid into place over the slip carrier. The slips are heldin this contracted position until openings 36 of the slip actuatorregister with the slips, and as soon as this registration occurs, theslips are permitted to move out or to expanded position, as the actuatoris moved into contact with flange I5 of the slip carrier.

When the slip actuator has been slid into this position sub 44 may bescrewed home on the upper threaded end of the frangible connectorelement 4l. When sub 44 is screwed home on the upper end of thefrangible connector element, its flange 48 forms a stop for limiting theupward movement of the slip actuator as shown in Fig. l.

The parts are so proportioned that when band 31 contacts with flange 48,the slips will occupy a position, with relation to slip carrier I4, suchthat they project into windows 36, whereby, as the slip actuator ismoved into contact with flange l5 of the slip carrier, the slips aremoved to'their fully expanded position as shown in Figs. I2 and 3. Whenthe actuator is moved up, the slips will be retracted; the amount ofretraction being limited by flange 48 of sub 44. When fully retracted(contracted) the slips occupy the position shown in Fig. l, at whichposition their outer toothed faces are substantially in line with theouter surfaces of band portions 31 and 38 of the actuator.

The bevel given to the upper surfaces 5| of the slips serves to relievethe slips and facilitate their movement outward while in contact withthe lower edge of band 31.

It will be apparent that the slips, together with the slip carrier andthe actuator, which holds the slips against vertical movement duringmovement of the slip carrier, thereby causing said slips to expand orcontract, constitutes a slip assembly which is secured tothe upper endof the packing element. It will also be apparent that the assembly madeup of the expander, its stem, the frangible connector and the sub servesas a support for the packing element, the stem of which is axiallyaligned With and freely passes through the slip carrier.

Lines 52 represent the wall of a well bore hole.

Operation K The plug, when in the condition illustrated in Fig. 1 thatis, with packing element Il! fully elongated and the slip actuator incontact with flange 48 of sub 44, whereby the slips are in'their fullycontracted position, is attached to a string of cable tools and loweredwithin the well bore hole to the desired position. As the plug is beinglowered Wiper springs 39 frictionally engage the wall of the well borehole, and hold slip actuator` `Vforced into the packing element.

connected to the expander stem, this upward stress foreshortens andexpands or increases the diameter of packing element I and causes theslip carrier to move up within the slips, which, being held againstmovement by band 31 of the slip actuator, are expanded to a point wherethey firmly grip the wall of the well bore hole.

As the sub and the expander with its stem attached thereto by means ofthe frangible connector element are drawn upward, the expanderforeshortens packing element I0 and increases its diameter until itcompletely seals the space between the conical portion of the expanderand portion I9 of the stem on the one hand and the Wall-of the well boreon the other. An upward jarring action is then applied to the cabletools with the result that the conical portion of the expander andportion I9 of its stem are tightly As the expander and its stem areelevated or travel upward with relation to the slip carrier, thebuttress-like threads of the stem pass through the segmented snubbingring which reengages said threads after each such upward movement, withthe result that any tendency to downward movement of the expander andits stem causes the snubbing ring to immediately grip the stem and thuslock the expander and its stem against such downward movement.

Continuation of the upward jarring action of the cable tools causes thefrangible connector element to yield and subsequently fracture at thepart weakened by drilled holes d5. Complete fracture of the frangibleelement separates the cable tools and sub 44 from the plug so that saidtools and sub may be withdrawn from the well bore hole, leaving the plugsecurely anchored in place.

After the expander has been moved to the position shown in Figs. 2 and 3in which the well bore hole is eifectively sealed against flow in anupward direction of oil, gas, water or other fluid trapped below theplug, such uid may enter the space formed by tubular member Il, plungerhead i6 and closure disk 22 through hole 24 drilled in the wall of saidtubular member. The pressure of this fluid beneath plunger head I6 tendsto force the expander and its stem further upward with relation to thepacking element and assists in maintaining the seal in permanent sealingcondition; upward movement of the plug being at all times prevented byengagement of the slips with the wall of the well bore hole.

From the foregoing, it will be apparent that the plug of this inventionmay be easily run to any desired position in a well bore and set andexpanded by upward stress exerted thereon by the tools on which it isrun. It will also be apparent that no anchoring or support means isneeded beneath the plug, and that upward jarring will not onlyeffectively tighten the plug, but that such jarring when continued aftersealing is accomplished will fracture the frangible connector elementand permit the withdrawal of the tools from the well bore hole, leavingthe plug securely anchored in place and in sealing condition therein.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a plug for a well bore hole, a tubular resilient packing element;a packing element expander having an upwardly tapered part locatedwithin the lower end of the packing element, a part located below saidtapered part and forming a plunger head, and a stem which extendsthrough the packing element and is provided with buttress threads; aconnecting sub and a frangible element connecting said sub to theexpander stem; a slip carrier loosely surrounding said stem andconnected to the upper end of the packing element; a tubular memberconnected to the lower end of the packing element, having its lower endclosed and having a bleeder opening extending through its side wall; asegmented snubbing ring carried within the slip carrier for cooperatingwith the buttress threads of said stem; slips carried by said slipcarrier, and a cage for said slips, carrying a series of wiper springsand functioning as an actuator for said slips.

2. In a plug 'for a well bore hole, a resilient tubular packing element,a packing element expander having a generally conical portion and astern extending upwardly therefrom through said packing element,frangible tubular means for connecting said expander stem to running intools, a slip assembly surrounding said stem and which includes a slipcarrier, slips mounted for sliding movement on said carrier, a slipactuator surrounding said carrier, mounted for movement longitudinallythereof and provided with Window-like openings for accommodating radialmovement of said slips, and wiper springs carried by said actuator andextending outwardly therefrom.

3. In a plug for a well bore hole, a resilient packing element, meansfor expanding said element into contact with the wall of the bore hole,a tubular frangible element for connecting said means to running intools, a slip assembly on said plug including a slip carrier, slipsmounted on said carrier, a tubular slip actuator surrounding saidcarrier and provided with openings through which said slips can move,and outwardly bowed springs carried by said actuator and adapted tofrictionally engage the bore hole wall; the construction and arrangementbeing such that when an upward stress is exerted on the slip carriersaid springs prevent relative movement between the carrier and the slipactuator thereby causing the slips to move into gripping engagement withthe bore hole wall.

4. In a plug for a well bore hole, a resilient packing element, apacking element expander having a stem extending upwardly through saidpacking element, snubbing means for preventing downward movement of saidstem with relation to said packing element, and a slip assembly on saidplug and coaxial with said stern for locking the plug against upwardmovement in the bore hole and comprising a slip carrier, slips mountedwithin upwardly and inwardly extending grooves of said carrier, a slipactuator engaging the tops and bottoms of said slips, and wiper springscarried by said actuator, projecting outwardly therefrom, and adapted toretard relative movement between said carrier and said actuator whenupward stress is exerted on said carrier whereby the slips are caused tomove radially outward into gripping engagement with the bore hole wall.

5. In a plug for plugging a well bore hole, slips, a slip expander, aresilient tubular packing element located below said expander, a packingelement expander having a generally conical portion and a stem whichextends upwardly therefrom through said packing element and the slipexpander and is provided with buttress threads, means including afrangible element for connecting said stem to running-n tools and whichis strong enough to transmit suicient upward stress to lock the plugwithin` the bore hole and expand the tubular packing element tocompletely close the opening between the packing element expander andthe well bore hole wall, and means co-operating with said buttressthreads for locking the packing element expander against downwardmovement. Y

6. In a plug for plugging a well bore hole, slips, a slip expander, aresilient tubular packing element located below and secured to saidexpander, a packing element expander having a generally conical portionand a stem which extends upwardly therefrom through said packing elementand the slip expander and is provided with buttress threads, meansincluding a frangible element for connecting said stem to running-intools and which is strong enough to transmit sufficient upward stress tolock the plug within the bore hole and expand the tubular packingelement to completely close the opening between the packing elementexpander and the well bore hole, a cage for said slips carrying wipersprings and functioning as an actuator for said slips,

and means carried by the slip expander and cooperating with saidbuttress threads for locking said stem against downward movement.

'7. In a plug for plugging a well bore hole, slips, a slip expander, aresilient tubular packing element located below and secured to saidexpander, a packing element expander having a generally conical portionand a stem which extends upwardly therefrom through said packing elementand the slip expander and is provided with buttress threads, meansincluding a frangible element for connecting said stem to running-intools and which is strong enough to transmit suicient upward stress t0lock the plug within the bore hole and expand the tubular packingelement to completely close the opening between the packing elementexpander and the well bore hole wall, a tubular member connected to thelower end of said tubular packing element, having a closed bottom and ableeder opening in its side wall, and means carried by the slip expanderand cooperating with said buttress threads for locking the packingelement expander against downward movement.

8. In a plug for plugging a well bore hole, a slip assembly whichincludes slips and a slip expander, a slip actuator extending above andbelow said slips, provided with openings through which said slips aremovable and carrying Wiper springs, a resilient tubular packing elementlocated below and attached to the slip expander, an imperiorate packingelement expander having a generally conical lower end and a stem whichextends upwardly through said packing element and said slip expander andis provided with buttress threads, a sub, a, frangible tubular elementconnecting said stem to said sub and which is strong enough to transmitsuilicient upward stress to lock the slip assembly within the well borehole and expand the tubular packing element to completely close theannular opening between the packing element expander and the wall of thelwell bore hole, and means co-operating with said buttress threads forlocking the packing element expander against downward movement.

9. In a plug for plugging a well bore hole, a slip assembly, a resilienttubular packingv element located below said assembly, a packing elementexpander having a frusto-conical portion and a stem which extendsupwardly from its top through said packing element and said slipassembly and is provided with buttress threads, means including afrangible element for connecting said stem to running-in tools'and whichis strong enough to transmit suiiicient upward stress to lock the slipassembly within the bore hole and expand the tubular packing element tocompletely close the annular opening between the packing elementexpander and the well bore hole wall, and means co-operating with saidbuttress threads for locking the packing element expander againstdownward movement.

FERDINAND J. SPANG.

